The Environment of Massive Quiescent Compact Galaxies at $0.1<z<0.4$ in the COSMOS Field

TL;DR

This study investigates the environments of massive quiescent compact galaxies at intermediate redshifts (0.1<z<0.4) using a comprehensive redshift survey in the COSMOS field, revealing that these galaxies reside in denser regions than typical quiescent galaxies.

Contribution

It provides the first detailed environmental analysis of massive quiescent compact galaxies at intermediate redshift, highlighting the role of mass in their environmental dependence.

Findings

Massive quiescent compact galaxies are found in denser environments than the general quiescent galaxy population.

Non-compact quiescent galaxies with similar stellar masses are found in similar environments.

The environment dependence is primarily driven by the massive nature of the compact galaxies.

Abstract

We use Hectospec mounted on the 6.5-meter MMT to carry out a redshift survey of red ($r-i>0.2$, $g-r>0.8$, $r<21.3$) galaxies in the COSMOS field to measure the environments of massive compact quiescent galaxies at intermediate redshift. The $>90\%$ complete magnitude limited survey includes redshifts for 1766 red galaxies with $r < 20.8$ covering the central square degree of the field; $65\%$ of the redshifts in this sample are new. We select a complete magnitude limited quiescent sample based on the rest-frame $UVJ$ colors. When the density distribution is sampled on a scale of 2 Mpc massive compact galaxies inhabit systematically denser regions than the parent quiescent galaxy population. Non-compact quiescent galaxies with the same stellar masses as their compact counterparts populate a similar distribution of environments. Thus the massive nature of quiescent compacts accounts for the environment dependence and appears fundamental to their history.